CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 957,704	$ 912,672
Short-term investments	504	479
Accounts receivable, less allowance for doubtful accounts of $14,600 and $14,000, respectively	449,664	537,564
Other receivables and current assets	214,492	268,522
Total current assets	1,622,364	1,719,237
Long-term assets:
Property and equipment, net	91,872	96,503
Operating lease right-of-use assets	125,323	137,730
Goodwill	3,110,736	3,038,306
Other intangible assets, net	689,398	694,865
Other long-term assets	228,207	225,119
Deferred income taxes	22,872	28,830
Total long-term assets	4,268,408	4,221,353
Total assets	5,890,772	5,940,590
Current liabilities:
Accounts payable	9,608	18,691
Accrued bonuses and commissions	51,856	112,491
Accrued income taxes	8,980	26,116
Other accrued expenses and liabilities	186,545	199,466
Deferred revenue	338,396	372,061
Total current liabilities	595,385	728,825
Long-term liabilities:
Deferred income taxes	103,649	110,321
Long-term operating lease liabilities	108,207	120,940
Long-term debt	753,327	798,118
Other long-term liabilities	79,986	84,514
Total long-term liabilities	1,045,169	1,113,893
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.01 par value; 2,000,000 shares authorized; zero shares issued or outstanding	0	0
Common stock, $0.01 par value; 300,000,000 shares authorized; 95,267,307 and 95,266,320 shares issued, respectively	953	953
Additional paid-in capital	1,381,590	1,434,203
Retained earnings	3,970,707	3,804,593
Treasury stock, at cost: 8,066,350 and 8,693,809 shares, respectively	(1,070,210)	(1,124,102)
Accumulated other comprehensive loss	(32,822)	(17,775)
Total stockholders' equity	4,250,218	4,097,872
Total liabilities and stockholders' equity	$ 5,890,772	$ 5,940,590